Method of determining wear patterns



March 28, 1961 c. G. DE HAVEN METHOD OF DETERMINING WEAR PATTERNS 2Sheets-Sheet 1 Filed July 28, 1958 CATALYST FIG. 3

INVENTOR.

C.G. DE HAVEN E WE N T n o K C 2ND COAT 3RD COAT 4TH COAT FIG. 2

ATTORNEYS March 28, 1961 c. G. DE HAVEN 2,976,716

METHOD OF DETERMINING WEAR PATTERNS Filed July 28, 1958 v 2 Sheets-Sheet2 y CATALYST IN FIG. 5 P76. 6

BARE METAL INVENTOR.

IST COAT C.G. DE HAVEN 2ND COAT By 3RD COAT 4TH COAT A TTORNEVS2,976,716 METHOD or DETERMINING rArrnnNs Clark G. De Haven,Bartlesville, kla., assignor'to'lhillips Petroleum Company, acorporation of Delaware- Filed July 28, 1958, Ser. No. 751,255

51. 6 Claims. (Cl. 73- 7) I This invention relates to a method fordetermining erosion.

patterns of wear of surfaces. In a more specific aspect the inventionrelates to a method for rapidly determining patterns of wear ofvarioussurfaceswhen contacted with an erosive medium.

In many industrial applications involving various surfaces such as metalconduits, T connections, stirred reaction vessels, etc., erosive fluidsor fluids in motion containing abrasive particles gradually wear downthe surfaces of the metal, usually with points of comparatively higherosion being encountered. In order to be able to correct the system forminimizing the points of high erosion or to otherwise counteract theeffect of high erosion at these points, it is desirable to determine inadvance where the points of high erosion will occur. In this wayequipment can be saved and plant production can be increased byanticipating the trouble in advance, thus avoiding costly down-time.

One industrial application in which the wear is particularly serious isin a well known fluidized catalyst cracking process wherein air beingintroduced to the regenerator vessel flows through a pipe which issubstantially horizontal in a portion of its length, and into said pipeis introduced through another pipe a flowing mass of finely dividedcatalyst which is pickedup by the air and introduced into theregenerator. During the combination of the catalyst and air streams inthe pipe leading to the regenerator there is encountered a seriouserosion problem near the area of confluence of the two streams. It isextremely desirable to be able to predict in advance where the highpoints of erosion occur so that additional wear plates can be installed.Moreover, if a rapid method of predicting wear of the surface isavailable, various bafile configurations can be tested in order to findan arrangement which will minimize the wear.

It is therefore an object of the invention to provide a method forrapidly determining the wear patterns of solid surfaces which undergowear while being contacted with erosive mediums. Other objects, as wellas aspects and advantages of the invention, will become apparent from astudy of the accompanying disclosure and drawings.

According to the invention, a surface to be subsequently contacted withan erosive medium is painted with successive uniform coats of paint ofcontrasting colors separated by transparent coats, and the surface isthen exposed to said erosive medium for a period of time sufiicient towear through at least one of said colored coats. The points of higherosion under the conditions of contact with the erosive medium or fluidare then easily seen by visual inspection.

The invention will be better understood by reference to the followingspecific examples and the figures which will be discussed in connectionwith the examples.

Figure l is a vertical section of a portion of a conduit employed formixing a powdered catalyst with air and transporting the catalyst-airmixture downstream. Fig- 2,976,716 Patented Ma.r.

ice

ure 2 is a plan'view of the portion of Figur'e lfbe'tween flangesshowing the pattern of erosion; A portionofthe top of the conduit wascut out and laid face up. This is Figure 3 showing the inside ofthe'cutout portion of the conduit. Figure 4 is an elevation ofa conduitsimilar to Figure 1, but the rate of en1argernent. from leftgto righto'f the'm ai'n conduit is more'gradual than in Figure 2.

Figure 5 is a 'view of the bottom half of Figure 4 sh owing the patternof erosion, and Figured is a view-of'the inside of the top half ofFigure 4-showing the patternof p In this example a conduit of theconfiguration of .Flg-

1 inc 1 having main conduit land catalyst introduction conduit 2 wastested with a finely divided silica-alumina powdered catalyst. Beforethe test the insideof :theqconduits werepainted with four coatsofpaintin contrasting colors, each coat being separated by a clear coat.In the tests the powdered catalyst was flowed in through line 2 at arate of about 200 pounds per minute, while air was flowed into the mainconduit 1 from the left to the right at the rate of about 430 cubic feetper minute. The expanding portion of conduit 1 had a diameter of 2inches on the small end and a diameter on the large end at the flange inthe right of the drawing of 5% inches. The length of conduit 1 betweenflanges at the top was 15 /2 inches. Conduit 2 had a diameter of 2 /2inches where it enters conduit 1. After completion of operation for atime sufficient to wear through several layers of paint at variouspoints, the test was discontinued and a top portion of the conduit ofFigure 1 was cut out. Figure 2 shows the wear pattern of the inside ofthe pipe with this top portion removed. Figure 3 shows the wear patternof the inside of the pipe for the removed portion. This figure is anaccurate sketch made from the photograph, as is Figure 2. From this testit was determined that the greatest amount of wear' is at the junctionof the catalyst conduit 2 and the main or air conduit 1, as shown by theclear areas in Figures 2 and 3 representing bare metal. Varying degreesof wear are shown elsewhere in the figures. The duration of the run inthis example was 1 hour.

Example II In this run the test was eflected in the same manner as inExample I except that the duration of the run was 4 hours. Also, it willbe seen that the main conduit 1a of Figure 4 used in this test was muchless sharply expanded than the conduit of Figure 1. The wear patterns ofthe bottom half (Figure 5) and the top half (Figure 6) of conduit 1ashows that the gradually expanding conduit 1a is much superior to themore sharply expanding conduit 1 of Figure 1, sincein 4 hours, insteadof 1 hour used in Example I, there waas only a small area worncompletely bare.

Although in the test conducted in Example I, the conduit 1 was cut opento observe the results, in most instances, including the tests of thepresent examples, it is possible to visually inspect the results withoutcutting open the equipment and thus requiring rewelding. This can bedone by inserting appropriate mirrors through one or more of the pipeopenings.

While the method has been described as employing successive coats ofcontrasting colors separated by clear coats, the clear separating coatsare not absolutely necessary, but are merely preferred.

Erosive mediums encountered and to which the invention is applicableinclude moving or flowing gases or liquids, which may or may not carryabrasive finely divided solids: gases containing entrained liquiddroplets; and flowing or gravitating solids such as refractory pebblesused in pebble heaters or solid catalyst particles such -in rthe lightof .the foregoing disclosurerand discussion without departing from thespirit or scope pr the (disclosure or from .thescope; of vthe .claims.

I claim: v} 1. Amethodfordetermining in advance areas offhigh erosion ofa:surface to be contacted by an erosive mediumiwhichicomprisespaintingisaid surface with suceessiveiuniform coats ofpaint of contrasting colors, 1 and exposing said surface to conditionscausing erosion by saiderosive medium for a time suflicient to :wearthrough at least one of said colored coats, whereby the areas of higherosion :are worn through"the most layers of said coats of paint.

2. A method 'of claim 1 wherein 'saicl surface is the inside surface ofa conduit.

3. A method for determining, in *advance, areas {of "high erosion-of asurfaceto be con'tacted by an erosive spasms 1 1 4 medium whichcomprises painting said surface with successive uniform coats of paintof contrasting colors separated by transparent coats, and exposing saidsurface to conditions causing erosion by said erosive medium for a timesufiicient to wear through at least one of said colored coats, wherebythe areas of high erosion are worn through the most layers of saidcoats'of paint.

4. A method of claim 3 wherein said surface is the inside surface o'f-aconduit.

Azmethod ofclaim .2 wherein theerosive medium comprises a fluid.

6. A method of claim 2 wherein the erosive medium comprises a solid.

References Cited in the file of this patent UNITED STATES PATENTS 1,961,333 Burns Iune,5, 1934 FOREIGN 'PATENTS 448,223 sGreatBritain June4, 1936

